swift: the multiparty transport protocol

see doc/index.html for marketing stuff, ideas and rants
    doc/swift.txt for protocol draft spec
    *.cpp for the actual code
    swift.cpp is the main exec file; may run as e.g.
        ./swift -t node300.das2.ewi.tudelft.nl:20000 -h \
        d1502706c46779d361a1d562a10da0a45c4c40e5 -f \
        trailer.ogg